Conventionally, it is common to scale down an image and then display it, for example, as a thumbnail or cause it to be displayed on a small-sized screen. If such processing scales down an image including an image part that shows characters, the characters also become smaller. Accordingly, the legibility of the characters is reduced. To prevent reduction in the legibility, it is proposed to set the scale-down factor of a character image part in an image to be larger than the scale-down factor of a background image part and then superimpose the scaled down character image on the scaled down background image (e.g., Patent Literature 1).